A ________ is a group of two or more atoms held together.
molecule
Molecules are the basis of chemistry. They are noted with an element symbol and a number for the total atoms.
What is the common name for the frozen form of carbon dioxide, which begins to smoke as it melts?
dry ice
The substance that we colloquially refer to as “dry ice” is actually the frozen form of carbon dioxide, and is about -100º F.
When introduced to our surroundings, the carbon dioxide begins to melt.
However, since it can only reach its liquid form in high-pressure environments, it changes directly from solid to gas.
What scale is used when measuring the acidity or basicity of water?
pH
Acids (low pH levels) and bases (high pH levels) have opposite properties and have the ability to cancel or neutralize each other.
pH values range from 0 to 14. Acids have pH levels that are below 7 while bases have pH levels above 7.
Examples:
* Orange juice is acidic and has a pH level of 4.
* Water is neutral and has a pH level of 7.
* Bleach is basic and has a pH level of 13.
In chemistry, what is the term used for a molecule made up of more than one type of atom?
compound
For example, a well-known compound is H2O (two hydrogen atoms and one oxygen atom form water).
On the other hand, an element is made up of only one type of atom (e.g. oxygen).
Which wealthy Swedish scientist and arms manufacturer of the 19th century invented dynamite?
Alfred Nobel
After his death, Nobel’s fortune was used to establish the Nobel Prizes, awards for cultural and scientific achievement.
Famous Nobel Prize winners include Albert Einstein, Marie Curie, and Martin Luther King, Jr.
In chemistry, what is the term used for the type of bond formed from the electrostatic attraction between oppositely charged ions in a chemical compound?
ionic bonds
(also known as electrovalent bond)
On the other hand, a covalent bond is formed when two atoms ‘share’ one or more electron.
What four states or forms does all matter assume?
- Solids
- Liquids
- Gases
- Plasma
A solid has a definite shape and volume. Think: ice
A liquid has a definite volume (you can’t compress water), but assumes the shape of its container. Think: water
A gas lacks both a defined shape and volume (it CAN be compressed). Think: water vapor
A plasma is an electrically charged gas. Think: lightning
What single element is both diamond and the graphite in your pencil made of?
carbon
(chemical symbol: C)
While both diamond and graphite are made purely of carbon, it’s HOW they are formed—and their resultant crystal structures—that explain their remarkable differences in hardness and appearance.
Diamonds are formed deep in the Earth’s mantle under extreme conditions of pressure, which cause the carbon to harden into cubic crystals.
Graphite is formed closer to the Earth’s surface, under less pressure, and so its atoms are arranged into hexagonal crystals.
Where does most of the oxygen in Earth’s atmosphere come from?
marine plants
Rainforests are responsible for roughly one-third (28%) of the Earth’s oxygen but a huge amount (from 50% to 85%) of the oxygen in the atmosphere is produced by marine plants.
What molecule in peppers gives them their heat/spiciness?
capsaicin
Capsaicin is a chemical irritant that produces a sensation of burning in any tissue with which it comes into contact.
Although it feels like it burns, this molecule is actually an alkaline, which is why drinking milk (slightly acidic) soothes our mouths after eating spicy food.
Aside from jewellery, what important application does gold have?
electricity conducting material
Most electronics contain gold in their circuit boards, including desktop and laptop computers, smartphones, TVs, and video game consoles.
What element was favored as a murder weapon in the Middle Ages because the symptoms of poisoning were similar to those of cholera, a rampant disease at the time?
arsenic
(chemical symbol: As)
Today, arsenic is predominantly in pesticides (like rat poison), as well as in pyrotechnics (fireworks), glass manufacturing, and wood preservation.
What is the common term for nitrous oxide gas, which is used as an anesthetic?
laughing gas
Nitrous oxide interacts with the brain’s neurotransmitters for dopamine, making you feel relaxed, euphoric, giddy, and/or lightheaded.
What are the building blocks of molecules?
atoms
Atoms are the smallest unit of matter that makes up molecules and chemical elements.
They consist of a central neutron(s) and one or more protons (positively charged particles), which make up its center (nucleus).
In orbit around the nucleus is (typically) an equal number of electrons (negatively charged particles).
A/n _______ is the simplest form of matter, consisting purely of a single kind of atom.
(e.g. Iron)
element
118 Elements have been identified and are catalogued on the Periodic Table.
What is the only metal that exists as a liquid at room temperature?
mercury
(chemical symbol: Hg)
Mercury was used in thermometers but because of a concern for safety (it’s highly toxic), this use was discontinued.
What gas famously smells like rotten eggs?
hydrogen sulfide
(chemical symbol: H₂S)
Most people think it’s sulfur that smells like rotten eggs, when in fact it is a gaseous molecule made up of two hydogen atoms and a sulfur atom.
And yes… it’s what makes your farts smell like rotten eggs, too!
What unique property of water explains why you should never freeze glass bottles containing liquids?
Water expands when it freezes
Unlike all other substances, which shrink when frozen, water expands due to the unique shape of its molecules.
Putting a glass bottle of water in the freezer is dangerous because the water has nowhere to go when it expands, causing the container to shatter and your beer / wine to leak out all over your freezer.
True or false:
It’s safe to microwave aluminum food containers.
FALSE
(You should NEVER put metal in the microwave!)
Microwaves emit radiation that excites the atoms in your food. This causes it to heat up and release energy in the form of steam.
Metal, on the other hand, cannot release energy in the form of steam and so it heats rapidly, producing sparks or even bursting into flame.
Water-based liquids can be described as acidic, neutral, or basic, with respect to pH.
Which of these best describes milk?
acidic
The slight acidy of milk makes it a good salve for spicy food because it neutralizes the alkaline molecules contained by hot peppers (capsaicin).
Dairy also contains casein, which breaks down capsaicin in the same way soap break down and washes away greasy residues.
What are the four elements common to all living things?
- carbon
- hydrogen
- nitrogen
- oxygen
(chemical symbols: C, H, N, O)
Biochemistry or Biological Chemistry is the study of chemical processes within and relating to living organisms.
